A spherical walking robot has been developed in recent years. At present, some spherical walking robots with different structures are invented. Generally, the spherical walking robot contacts the ground with points which results in pure rolling friction with little resistance, and the spherical walking robot is flexible and convenient to be driven and turned around, and can be driven to walk in all directions and turned around with zero turning radius, so the spherical walking robot can walk in all directions on 2-dimensional ground and easily pass through flexuous channel whose caliber is a little larger than the diameter of the spherical walking robot. Besides the spherical walking robot is highly adaptive to various road conditions, so it is expected to become an ideal delivery vehicle moving on rough ground in the future, however application of the spherical walking robot is still restricted to a great extent in some special circumstances.
Besides the spherical walking robot, multiplied robot or robot with mechanical arms also has attracted wide attentions, researches and applications so far. The multiplied robots or robot with mechanical arms is highly adaptive to surroundings; the mechanical arms can perform various functions like the arms of human beings, and can do many special jobs. But the multiplied robots or robot with mechanical arms is not characterized in omni-directional walk in two dimensions and zero-radius turning around just like a spherical robot, which limits flexibility of the multiplied robot or robot with mechanical arms in many occasions. So the multiplied robot or robot with mechanical arms requires a good moving carrier for using in some circumstances.